2031 research outputs found
Sort by
Mechanical Behavior of Concrete Beams with HDPE Plastic Waste as Partial Fine Aggregates Replacement
No full textThis study is related to using HDPE plastic bag waste applied to building structural components, specifically concrete beams. An innovation utilizes HDPE plastic waste not in shredded form but by taking advantage of the rigid physical properties of HDPE plastic waste after it is burned, crushed, and sieved to the size of sand to be used as a partial replacement (substitution) for fine aggregate (sand). The type of research conducted is experimental quantitative research to determine the flexural capacity of concrete beams made from HDPE plastic bag waste as a partial replacement for fine aggregates using the normal flexural strength testing method with two-point loading. The test specimens prepared were concrete beams with dimensions of 15 × 15 cm cross-section and 65 cm in length, with varying amounts of HDPE plastic bag waste replacement: 0.00% (normal concrete), 0.50%, 0.70%, and 0.90% of the weight of the sand. The concrete beam specimens were cured using a wet curing method and tested at 14 and 28 days of age. The results showed that at 14 days, the concrete beam specimens with variations of 0.00%, 0.50%, 0.70%, and 0.90% achieved flexural strengths of 3.16, 3.35, 2.91, and 2.97 MPa, respectively. Meanwhile, at 28 days, the specimens with variations of 0.00%, 0.50%, 0.70%, and 0.90% reached flexural strengths of 3.39, 3.95, 3.06, and 3.07 MPa, respectively. The highest flexural strength was achieved by the concrete beam specimen with a 0.50% substitution variation, both at 14 and 28 days, with values of 3.35 and 3.95 MPa, respectively, exceeding the flexural strength of the beam without HDPE plastic waste substitution (0.00%)
eXplainable Machine Learning for Real Estate: XGBoost and Shapley Values in Price Prediction
Get PDFThis study examines the application of eXplainable Artificial Intelligence (XAI) in property market research, utilizing housing transaction data from Quarry Bay, Hong Kong. The research employs the XGBoost algorithm to predict property prices and subsequently computes Shapley Additive Explanations (SHAP) values to quantify feature importance. A beeswarm plot is used to visualize the distribution of SHAP values, uncovering complex relationships between prices and property characteristics. The findings demonstrate how features such as square footage and property age contribute to average price predictions, offering valuable insights for urban planning and real estate decision-making. In contrast to the traditional black-box models, this study integrates XAI methodologies to enhance model interpretability, thereby fostering trust in AI-driven market analyses. The novelty of this research lies in its combination of machine learning and explainable techniques, bridging the gap between predictive accuracy and interpretability in property valuation. By advancing data-driven decision-making, this study underscores the potential of XAI in promoting transparency and facilitating informed policymaking in the property market. Doi: 10.28991/CEJ-2025-011-05-022 Full Text: PD
Revolutionizing Self-Healing Asphalt: Optimized Encapsulated Rejuvenators for Enhanced Durability and Sustainability
No full textIn an era where sustainable infrastructure is crucial, self-healing asphalt emerges as a transformative solution to enhance pavement longevity and reduce maintenance costs, addressing the global challenge of deteriorating road networks. This study presents a pioneering investigation into the development and performance evaluation of encapsulated rejuvenators for self-healing asphalt, utilizing two distinct compositions; waste cooking oil (WCO) and Fischer-Tropsch bright stock oil (FTBSO), across three capsule sizes (1 mm, 2 mm, and 3 mm). Through the experimental tests on compressive strength, thermal stability, and rupture resistance under wet conditions, the ongoing study highlights the critical influence of capsule size and composition on the mechanical performance, as well as the resistance to degradation and oxidation under similar asphalt production conditions, including applied stresses and temperatures. The findings indicate the superior performance of 3 mm FTBSO-based encapsulated rejuvenators, which exhibit exceptional compressive strength (155 N), minimal weight loss (2% at 200° C after 1-hour short-term aging), and high rupture resistance (80 minutes to break under moisture at 100° C), making these capsules ideal for withstanding mechanical and thermal stresses, while ensuring effective crack repair. In addition, both 2 mm and 3 mm FTBSO- and WCO-based rejuvenator capsules demonstrated high resistance to compressive stresses, excellent thermal stability, and strong rupture resistance, making these capsules suitable for self-healing asphalt applications. In contrast, 1 mm WCO-based rejuvenator capsules exhibited the lowest compressive strength (32 N), the highest weight loss (10% after 1 hour of short-term aging at 200° C), and the fastest rupture under moisture (18 minutes to break at 100° C), making these capsules the least suitable for self-healing asphalt applications
Optimizing Waste Foundry Sand in Concrete Considering Strength Properties for Sustainable Green Structures
Get PDFIncorporating waste foundry sand (WFS) into concrete is a sustainable approach to enhance green construction practices. Waste foundry sand is a byproduct of the metal casting industry and is often discarded in landfills, posing environmental concerns. Using it as a partial replacement for natural sand in concrete addresses both waste management and resource conservation. In this research paper, advanced machine learning models have been reported on the soft computing of the optimal waste foundry sand in concrete based on strength properties for sustainable green structures. The machine learning techniques such as “Group Methods Data Handling Neural Network (GMDH-NN)”, “Support Vector Machine (SVM)”, “K-Nearest Neighbors (KNN)”, “Tree Decision (Tree)” and “Random Forest (RF)” were applied on a database for the compressive strength containing 397 records, for elastic modulus containing 146 records, and for split tensile strength containing 242 records. Each record contains C-Cement content (kg/m³), WFS-Waste foundry sand content (kg/m³), W-Water content (kg/m³), SP-Super-plasticizer content (kg/m³), CA-Coarse aggregates content (kg/m³), FA-Fine aggregates content (kg/m³), TA-Total aggregates content (kg/m³), and Age-The concrete age at testing (days), considered as the input parameters and CS_WFS-Compressive strength of waste foundry sand concrete (MPa), E_WFS-Elastic modules of waste foundry sand concrete (GPa), and STS_WFS-Split tensile strength of waste foundry sand concrete (MPa), which are the output parameters. A 75/25 partitioning pattern for train/test of the database was used in line with established rules. At the end of the model operation, it can be observed that kNN, SVM, and RF were paramount in terms of performance and therefore outclassed the other models in the three-state strength condition of the WFS cement concrete. Hence, these were selected as the decisive models for the prediction of the compressive strength, elastic modulus, and splitting tensile strength of the WFS cement's concrete. The sensitivity analyses showed that Age, WFS/C and CA/C are more impactful on the compressive strength, Age, FA/TA, and W/C are more impactful on the elastic modulus; and 1000SP/C, WFS/C, and W/C are more impactful on the splitting tensile strength of the WFS cement concrete. Generally, these models provide a foundation for optimizing material use, ensuring quality, and meeting environmental goals. Industries leveraging these tools can produce eco-friendly, high-performance concrete while addressing waste management challenges and reducing their carbon footprint
Statistical Analyses of the Euphrates River Entry and Hydrological Drought Assessment (SDI)
No full textThe Euphrates River, a vital water resource in Iraq, has seen a marked decline in flow over the past two decades due to climate change and upstream interventions. The aim of this study is to investigate the impacts of changing rainfall patterns and temperature on the river's water balance, flow regime, and drought index. Results show an annual rainfall decline of 0.15 mm, while maximum and minimum temperatures increased annually by 0.086°C and 0.066°C, respectively, according to the Mann-Kendall trend and Sen’s slope tests. Monthly rainfall generally decreased, except for slight increases in April (0.32 mm) and October (0.018 mm). July 2017 and August 2003 saw peak temperatures of 45.1°C, while January 2008 recorded a minimum of -1.8°C. The box-and-whisker plot revealed high rainfall variability in November and February. River flow dropped by 41%, mainly due to the Turkish GAP project and climate impacts. HEC-DSS software analyzed flow duration over 32 years, and Pearson’s correlation showed low associations between flow rate and temperature (-0.36) and rainfall (0.29). The Drinc program was utilized to calculate the Standardized Drought Index, which identified that the water year 1987–1988 was very wet, while it detected severe droughts in 2014–2015 and 2021–2022. Overall, climate change and upstream dam construction have significantly reduced Euphrates River discharges, intensifying drought conditions in the region. The long-term changes in precipitation and air temperature in the study area support the observed streamflow trends. The findings of this study demonstrate that a cooperative approach to international water management between the riparian states is crucial
Simplified and Rapid Modeling of Road Embankments Slope Safety Factor Using Regularized Regression Techniques
Get PDFThe primary objective of this research is to examine the viability of simplified regularized regression models in predicting the slope safety factor of road embankments. The methodology involves developing and comparing several regularized linear regressions against conventional methods. A total of 276 data points are collected from the literature, and 70% of these are utilized for model training, while 30% are employed for testing. The findings indicate that these models yield results better than established approaches, with Stochastic Gradient Descent and Bayesian Ridge achieving strong performances. This study provides an alternative technique that offers rapid and manually solvable equations, thus enhancing practical adaptability for routine professional tasks. The novelty lies in bridging the gap between traditional finite element-based investigations and emerging data-driven methods, demonstrating that regularized regression can be both simple and sufficiently accurate. Overall, the study outcomes emphasize the significance of these advanced yet computationally light models for road embankment stability assessments, presenting a valuable and time-efficient tool for practitioners
Efficacy of Plastic Waste Strips Towards Enhancement of Shear Capacity of Reinforced Concrete Beams
Get PDFThe amount of plastic waste produced worldwide has been steadily rising. Manufacturing processes, service industries, and municipal solid waste produce a significant amount of waste plastic. One common construction and industrial waste that could be employed as shear reinforcement in concrete beams for specified purposes is the plastic waste strips, since they have relatively high tensile strength. Such plastic strips are used to tie clay bricks, floor finishing tiles, walkway finishing blocks, curbstones, and so on in different industrial products. This study examines an approach that uses plastic waste strips in place of conventional stirrups to enhance the shear performance of reinforced concrete (RC) beams. A set of shear tests was performed on carefully constructed 150 mm width × 225 mm depth × 1400 mm length beam specimens to evaluate failure mechanisms, modes of failure, crack patterns, and shear strength. All beams have the same flexural requirements, so they were ensured to fail by exceeding their shear strength under the applied load. This study examined five concrete beams that were reinforced internally using plastic waste strips in the shear region, as well as one control beam. The tested beams were reinforced using various strip spacings and configurations. The results of the tests indicated that increasing the plastic waste strips improved the concrete section shear strength. As the number of plastic strips in the section increases, the distance between each strip is drastically reduced, increasing the shear capacity of the beam. The experimental results indicate that the beam with six vertical plastic waste strips in its section has a 75% higher shear strength capacity than the reference beam without any transverse reinforcement. In addition, shear resistance is higher in the beam with plastic strips at 45° and 135° inclined angles than in the beam with vertical plastic strips in the same amount of plastic strips. Based on these findings, reinforced concrete beams can be utilized for specific purposes by employing plastic waste strips as transverse reinforcement to resist internal shear forces
Life Cycle Assessment of Phosphogypsum as Filler Material for Coal Fly Ash-Based Geopolymer
No full textThe global accumulation of phosphogypsum (PG), with annual generation exceeding 175 Mt/year, presents significant environmental challenges. While studies have demonstrated PG's potential as a filler material in geopolymer composite, comprehensive environmental impact assessments of such valorization approaches remain limited. This study presents the first comparative life cycle assessment (LCA) of acid- and alkali-activated PG-CFA geopolymers in the context of sustainable industrial waste management. Geopolymer technology can eliminate the need for traditional landfilling of PG in coastal areas and, therefore, reduce their negative environmental impacts. LCA was conducted to assess the impacts of repurposing 1kg functional unit of PG as geopolymer precursors coupled with acid- and alkali-based activators compared to the current disposal practices of these solid wastes. The inventory was modeled after a phosphoric acid plant using the wet dihydrate process, a coal-fired power plant, and a laboratory-scale coal fly ash-phosphogypsum geopolymer (FAPG) synthesis upscaled for industrial application. The most number of environmental benefits was observed for acid FAPG particularly via reductions in CO2-eq emissions by 40%, 90% in energy consumption, and 36% in mineral resource extraction. Alkali FAPG excelled in water acidification and scarcity by 60% and it could outperform acid FAPG environmentally via sensitivity analysis under a similar formulation blend. Further research can focus on optimizing FAPG formulation, finding alternatives for the acid and alkali activators, and reviewing industrial standards for widespread FAPG applications. These results imply the potential of integrating FAPG manufacturing in PG- and CFA-generating industries to emulate a circular economy
Assessing Urban Characteristics: The C-DNA As a Catalyst of Urban Morphogenesis
No full textHistoric city centers are cultural archives where built forms and spatial practices hold the collective memory of generations. In Baghdad, the concept of Cultural DNA (C-DNA) is a tool to understand how cultural codes are the generative rules that shape the evolution and persistence of the historic urban fabric. This research explores the role of C-DNA as a trigger of urban morphogenesis in Rusafa, the historic heart of Baghdad, by looking into how cultural values underpin spatial continuity, change, and adaptability. The study uses Space Syntax methodologies with DepthmapX, supported by historical maps, surveys, and field observations, to analyze two morphological stages of Rusafa: 1850 and now. Through axial analysis, the research measures integration, connectivity, choice, and control to evaluate key urban characteristics: centrality, hierarchy, privacy, and territoriality. This comparative approach highlights both continuity and disruption in the historic fabric. The results show that cultural nuclei (mosques, markets, khans, and schools) are still the central points of the city, anchoring movement and interaction across centuries. Despite the disruption caused by modern interventions like Al-Rashid Street, the organic urban fabric still holds the capacity to sustain privacy, territoriality, and hierarchical spatial arrangements. The findings prove C-DNA is not a metaphor but an operational system that generates urban order and resilience. The study concludes that understanding C-DNA is crucial for developing sustainable revitalization strategies in Baghdad and similar Islamic historic cities. By treating culture as the city’s genetic code, planners and policymakers can design interventions that preserve cultural identity while accommodating urban needs
A Study on the Impact of Crystalline Hydrophilic Additive and Microcapsules on Concrete Freeze-Thaw Durability
Get PDFThis paper evaluates the effectiveness of a crystalline hydrophilic additive and chemical microcapsules in enhancing concrete’s freeze-thaw resistance at both material and structural levels. Three concrete mixes were tested: a reference mix, one with the crystalline additive and one with microcapsules. Cubic specimens were tested for compressive strength, water absorption and relative dynamic modulus of elasticity before, after and during 56 freeze-thaw cycles (according to CEN/TR 15177). The reinforced concrete beams underwent the same freeze-thaw regime and were tested under displacement-controlled cyclic loading to evaluate residual capacity and serviceability. Although both additives improved freeze-thaw resistance, beams with the microcapsule performed better on most criteria, including increased stiffness (+14%), load-bearing capacity (up to +22%) and ductility after freeze-thaw loading. Notably, all mixes showed an unexpected increase in compressive strength after cycling. Although the microcapsules provided the best overall performance, the crystalline additive was more effective in reducing water absorption. The study highlights the practical applicability of microcapsules for structural elements and demonstrates their potential to improve performance properties under harsh environmental conditions. The research novelty lies in the dual-level evaluation – material and structural – and the systematic comparison of two innovative additives, allowing a more comprehensive understanding of their performance under freeze-thaw conditions